Sink strainer



Aug. 25, 1970 w. T. RICHARDS 3,525,105

SINK STRAINER Filed May 5. v1968 28 FIG. 3 1o r 62 6O 36 58 56- l 3 3 32 I 18 4P l 18 ?4 3? I INVENTOR. WILLIAM T. RICHARDS United States Patent 3,525,105 SINK STRAINER William Thomas Richards, Weston, Ontario, Canada, as-

siguor to Premier Tool & Die Limited, Toronto, Ontario, Canada Filed May 3, 1968, Ser. No. 726,427 Int. Cl. A47k 1/14 US. Cl. 4-287 4 Claims ABSTRACT OF THE DISCLOSURE A sink strainer has a stern, formed of plate spring steel, which has a portion of larger diameter than a slot in the sink base; contact between this portion of the stem and the edge of the slot provides the raised position. The sink strainer seals with the sink base by forcing the stem through the slot and the stem is tapered inwardly above the portion of larger diameter so that the sideways pressure exerted by the edge of the slot on the tapered portion forces it downward to accentuate the sealing position.

FIELD OF THE INVENTION This invention relates to sink strainers of the type which in a supported raised position in the sink allows the water to escape if solid material of a size sufficient to cause blockage of the connected drain is caught in the strainer. In the lowered position the strainer forms a seal with the sink to prevent the escape of water.

DESCRIPTION OF PRIOR ART To effect positioning of the sink strainer in the manner already described, various constructions have been employed. Probably the most widely used is one where the sink has a retangular slot centrally disposed in the base of the lower cup portion the slot being surrounded by a number of apertures providing communication between the sink and the drain. The upper edge of the cup portion flares outwardly to provide a seating against which the underside of the cup shaped strainer may form a seal.

The strainer has a centrally disposed stem on its underside, the stem having a lower portion which is substantially rectangular but somewhat smaller than the rectangular slot in the base of the sink. The stem terminates in a square portion having sides the same as the minor dimension of the connecting rectangular portion, thus providing a pair of opposed shoulders with the junction thereof. The diagonal of the square portion of the stem is greater than the minor dimension of the rectangular slot.

To provide the lower sealing position, the rectangular stem is positioned in line with the rectangular 'slot and passes therethrough; to maintain the strainer in the raised position the stem is turned at right angles so that the shoulders rest adjacent the opposed edges of the rectangular slot which forms its major dimension. The centering action in the two positions is provided by the inability of the square end of the stem to turn completely in the rectangular slot.

However, it has been found in this type of strainer that the seal in the lowered position is not completely effective. The reasons are a combination of flexing of the sink base and the lightness of the sink strainer, both the sink and the strainer being now-a-days preferably made from very thin stainless steel.

SUMMARY OF THE INVENTION It is the object of the invention to provide a sink strainer which provides an effective seal in the lowered position.

The invention consists of providing a stem on the underside of the sink strainer which stem has an intermediate portion wider than the minimum dimension of the aperture or slot in the base of the sink. The stem slopes inwardly above the intermediate portion and the stem is sufliciently resilient in the transverse direction to enable it to be forced through the slot. The raised position of the sink strainer is provided by the intermediate portion resting on the sink base whereas the sealing position is provided by forcing the stem through the slot to effect a sealing relationship between the underside of the sink strainer and the base of the sink, which sealing relationship is accentuated through the sidewayspressnre exerted on the sloping portion of the stem by the edges of the slot in the sink, which pressure tends to force the stem downwards.

BRIEF DESCRIPTION OF THE DRAWING The invention will now be described in relation to the accompanying drawings wherein:

FIG. 1 is a perspective view of a preferred embodiment of a sink strainer constructed according to the invention.

FIG. 2 is a cross-sectional view of the sink strainer shown in FIG. 1, situated in the base of a sink in the raised position.

FIG. 3 illustrates the sink strainer shown in FIG. 1 situated in a sink base in the sealed position.

FIG. 4 is an alternative embodiment of the sink strainer constructed according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more particularly to FIGS. 1 and 2, the sink strainer generally denoted by the numeral 10 and of substantially cup shaped formation, comprises a base 12 which is integral with a rimmed upstanding wall 14. Perforations 16 are provided between the base 12 and the wall 14 so that when the water in the sink escapes into the drain 18 in the raised position of the strainer 10, the perforations 1-6 serve to trap solid material and prevent it entering the drain 18.

Centrally disposed in the strainer 10 and extending upwardly from the base 12 is a circular rod 20 having an enlarged upper portion 22, the side of which has serrations 24. The rod 20 provides a means of manual manipulation for the strainer 10, as described hereunder, the serrations 24, of course, giving an improved grip.

Secured to the underside of the sink strainer 10 and positioned inward of the perforations 16, is a circular rubber washer, 26. The outer surface, 28 of the rubber washer 26 tapers in a downward direction as illustrated in FIG. 2. The washer 26 is held in position against the underside of the sink strainer 10 by means of a flanged collar 30.

Depending downwardly and centrally disposed in the flanged collar 30 is a spring member, generally denoted by the numeral 32, a preferred form of which is more particularly shown in FIG. 1. The spring member or stem 32 is preferably made from a single piece of plate spring steel formed to provide a diamond configuration at its lower end, having opposed sides 34 and 36, diverging from the tip 38.

The opposed sides 34 and 36 then slope inwardly and upwardly into opposed sides 40 and 42 which in turn blend into upwardly and outwardly disposed sides or ends 44 and 46, terminating in horizontally disposed portions 48 and 50. The spring member 32 is held in place by the head 52 of a rivet 54, the shank of which is driven into the rod 20 through the portions 48 and '50 of the spring member 32 and also the base 12 of the strainer 10.

The base of a conventional sink, generally denoted by the numeral 56, is cup shaped in formation having a base wall, 58 and a normally disposed upwardly extending side 60 which is brazed or otherwise attached to the interior of the drain 18. The side 60 merges into an outwardly and upwardly disposed portion 62. The junction of the side 60 and the outwardly disposed portion 62, lies in a vertical plane intersecting the sloping side 28 of the rubber washer 26.

The sink base wall 58 has an aperture 64 the width of which is less than the maximum width across the opposed sides 34 and 36 of the spring member 32. As illustrated more particularly in FIG. 2, the edge of the aperture 64 is preferably folded back on its underside to provide a smooth edge.

In the alternative embodiment shown in FIG. 4 sides 44 and 46 of the spring member 32 are riveted to an extension 66 of the rod 20 which extension 66 protrudes from the underside of the base 12 of the sink strainer 10.

The raised position of the strainer in relation to the base of the sink 56 is attained when the opposed divergent sides 34 and 36 of the spring member 32 rest on the sides of the aperture 64 the width of the latter being less than the maximum width across the opposed sides, 34 and 36 of the spring member 32.

The sealing position is obtained by forcing the spring member 32 through the aperture 64 at which time the rubber washer 26 bears against the junction of the side 60 with the outwardly disposed portion 62 on the base 56 of the sink. The sealing action is accentuated through the sideways pressure exerted on the inwardly opposed sloping sides 40 and 42 of the spring member 32 by the edge of the aperture 64 in the sink base 56.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination, a conventional sink having a drainage aperture in the bottom thereof, a cup shaped strainer dimensioned so that its underside forms a seal with said drainage aperture, a depending stem on the bottom side of said strainer, means fixed in said strainer for manual manipulation thereof; said stem having a portion dimensioned to rest on the upper edge of a second aperture formed in the base wall of said sink maintaining the underside of said strainer out of sealing relationship with said drainage aperture, said stem being compressible to permit said portion to be forced through said second aperture to bring said strainer into sealing relationship with said drainage aperture, said stem having a converging section above said portion whereby the edge of said second aperture bears against said section to urge said stem downwards to accentuate said sealing relationship; said stem consisting of a continuous strip of resilient material having a diamond shaped lower end open at one corner with upwardly disposed ends, the diagonal of said diamond shaped lower end through the open corner being vertically directed with said open corner uppermost, said upwardly projecting ends being attached on said bottom side of said strainer at a central location thereof.

2. The combination according to claim 1, wherein the underside of said strainer has a washer of rubber-like material to form said seal.

3. The combination according to claim 1, wherein said portion and said converging section of said stem are made of spring steel.

4. The combination according to claim 1 wherein said edge of said second aperture is formed by folding over to provide a smooth surface.

References Cited UNITED STATES PATENTS 1,593,087 7/1926 Logan 4291 1,704,529 3/1929 Brotz 4287 1,760,651 5/ 1030 Pasman 4-287 1,773,547 8/ 1630 Robertson 4-287 2,450,392 9/ 1948 Donahue 4-287 2,905,951 9/1959 Weddendorf 4287 3,027,569 4/ 1962 Lantz et al. 4287 3,096,527 7/ 1963 Eynon 4-287 FOREIGN PATENTS 1,031,993 6/ 1966 Great Britain.

625,068 2/ 193 6 Germany.

614,816 6/1935 Germany.

642,311 7/ 1962 Italy.

LAVERNE D. GEIGER, Primary Examiner D. B. MASSENBERG, Assistant Examiner 

